It is known that bevel gears can be machined using a grinding tool. So-called cup grinding wheels are frequently used in this case.
In the grinding of bevel gears, a differentiation is made between so-called grinding in the plunging method for non-generated gear teeth and grinding in the rolling method for generated gear teeth.
During the grinding of spiral-toothed bevel gears, the concave tooth flank of a tooth gap is created with the outer circumferential surface and the convex tooth flank of the tooth gap is created with the inner circumferential surface of a cup grinding wheel. If this is performed in two-flank cutting, also called completing, which is typical in the case of plunging grinding of crown gears, but also in the generating of pinions, both tooth flanks of the tooth gap are thus ground simultaneously. In single-flank grinding or single-sided methods, in contrast, either only the concave or only the convex tooth flanks of the tooth gap are ground.
FIG. 1A shows a schematic illustration of an approach in which a cup grinding wheel 2 rotates about a wheel center point M1. The axis of rotation R1 of the tool spindle (not shown) is perpendicular to the plane of the drawing and extends through the wheel center point M1. The rotation of the cup grinding wheel 2 about the axis of rotation R1 is identified in FIG. 1A with ω1. The corresponding axial drive is identified hereafter with A1. At the moment shown, a concave tooth flank 5.1 of the workpiece 1 is being ground.
FIG. 1B shows a schematically simplified section along line X1-X1 through a part of the cup grinding wheel 2, wherein rounded areas of the corners, which are necessary in practice and are also present, are not shown. The asymmetrical profile 8 of the cup grinding wheel 2 can be seen in FIG. 1B. The outer flank on the outer circumference 8.1 of the cup grinding wheel 2 is used to grind the concave tooth flanks 5.1 of the workpiece 1. The inner flank on the inner circumference 8.2 of the cup grinding wheel 2 is used to grind the convex tooth flanks 5.2 of the workpiece 1.
There are areas of application in which the demands on the quality of the bevel gears are particularly high. The expenditure for producing such bevel gears is correspondingly large and the machines used must fulfill numerous criteria.
So-called dual-spindle grinding machines are frequently used in single-flank grinding, which, as the name already indicates, have two tool spindles for accommodating one grinding tool each. In such a dual-spindle grinding machine, a workpiece in a chuck can firstly have the concave flanks be machined using a first grinding tool and subsequently have the convex flanks be machined using a second grinding tool, for example. Because re-chucking of the workpiece is not necessary, gearwheels of high quality can be produced. Since the workpiece does not have to be re-chucked, the concentricity error during the machining using the first grinding tool and subsequently during the machining using the second grinding tool is identical.
Such dual-spindle grinding machines are usually very specialized machines, which are costly, on the other hand, and which are not flexibly usable for other machining methods, on the other hand.
The demand exists for also being able to produce bevel gears having comparable quality on so-called single-spindle grinding machines. Unfortunately, this has heretofore not been possible or has only been possible with great effort on a single-spindle grinding machine. In addition, in a single-spindle grinding machine, a change from a first grinding tool to a second grinding tool must be completed, which requires a refitting time, during which the machine is not usable.